An Anna's hummingbird (Calypte anna) shows off the iridescent feathers on its head and back while resting on the branch of a rhododenron in Snohomish County, Washington. All hummingbirds have iridescent plumage, which reflects certain wavelengths of light. Several features of the feathers result in the iridescence. Barbules, which are flat in most birds, are angled to form a V shape in hummingbirds. Also, the surface of the barbules is covered with microscopic discs containing tiny air bubbles that amplify certain colors of light and cancel out others.